CN112835177B

CN112835177B - Imaging lens system

Info

Publication number: CN112835177B
Application number: CN202011259105.0A
Authority: CN
Inventors: 郑弼镐; 赵镛主; 黄孝真
Original assignee: Samsung Electro Mechanics Co Ltd
Current assignee: Samsung Electro Mechanics Co Ltd
Priority date: 2019-11-25
Filing date: 2020-11-12
Publication date: 2022-09-09
Anticipated expiration: 2040-11-12
Also published as: US11828917B2; TW202120996A; CN112835177A; TW202346952A; CN115268037A; TWI814225B; US20240061218A1; US20210157104A1; KR20210063888A; KR102608095B1; TW202219587A; CN213659078U; KR102418603B1; TWI757869B; CN115268036A; KR20220095178A

Abstract

The imaging lens system includes a first lens, a second lens having a negative refractive power, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens having a concave object-side surface in a paraxial region, which are arranged in this order in a direction from the object side to the imaging surface. The imaging lens system satisfies TTL/IMGHT <1.5, where TTL is a distance from an object side surface of the first lens to the imaging plane, and IMGHT is half a diagonal length of the imaging plane.

Description

Imaging lens system

Cross Reference to Related Applications

This application claims the benefit of priority of korean patent application No. 10-2019-0152526, filed on 25.11.2019, to the korean intellectual property office, the entire disclosure of which is incorporated herein by reference for all purposes.

Technical Field

The following description relates to an imaging lens system including eight lenses.

Background

The miniature camera may be mounted on a wireless terminal device. For example, a small camera may be mounted on each of the front and rear surfaces of the wireless terminal device. Since such a small camera can be used for various purposes, it is required to have performance similar to that of a general camera in order to acquire an image of a landscape, an image of an indoor portrait, and the like. However, since the installation space may be limited due to the limited size of the wireless terminal device, it may be difficult for the small camera to achieve high performance. Therefore, it is required to develop an imaging lens system that can improve the performance of a compact camera without increasing the size of the compact camera.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

An imaging lens system is provided which can improve the performance of a compact camera.

In one general aspect, an imaging lens system includes, in order in a direction from an object side to an imaging surface, a first lens, a second lens having a negative refractive power, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens having a concave object-side surface in a paraxial region. The imaging lens system satisfies TTL/IMGHT <1.5, where TTL is a distance from an object side surface of the first lens to the imaging plane, and IMGHT is half a diagonal length of the imaging plane.

The second lens may have a concave image side surface.

The fourth lens may have a positive refractive power.

The fifth lens may have a concave image side surface.

The sixth lens may have a negative refractive power.

The seventh lens may have a positive refractive power.

The imaging lens system may satisfy 0.5< f1/f <1.0, where f is a focal length of the imaging lens system, and f1 is a focal length of the first lens.

The second lens may have an abbe number of less than 40.

The imaging lens system may satisfy 0.05< TTL/FOV <0.2, where FOV is a field angle of the imaging lens system.

The imaging lens system may satisfy 0.2< T8/T7<0.9, where T7 is a thickness of the seventh lens at a center thereof along the optical axis, and T8 is a thickness of the eighth lens at a center thereof along the optical axis.

In another general aspect, an imaging lens system includes, in order in a direction from an object side to an imaging surface, a first lens, a second lens having a negative refractive power, a third lens, a fourth lens, a fifth lens, a sixth lens having a concave image side surface, a seventh lens, and an eighth lens having a concave object side surface.

The F-number of the imaging lens system may be 1.7 or less.

The imaging lens system may satisfy-4.0 < f2/f1< -2.0, where f1 is a focal length of the first lens, and f2 is a focal length of the second lens.

The imaging lens system may satisfy 0.2< f2/f3<0.5, where f2 is a focal length of the second lens, and f3 is a focal length of the third lens.

The imaging lens system may satisfy-5.0 < f6/f7< -2.0, where f6 is a focal length of the sixth lens, and f7 is a focal length of the seventh lens.

The imaging lens system may satisfy-3.0 < f7/f8< -1.0, where f7 is a focal length of the seventh lens, and f8 is a focal length of the eighth lens.

In another general aspect, an imaging lens system includes, in order in a direction from an object side to an imaging surface, a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a negative refractive power, a fourth lens having a refractive power, a fifth lens having a refractive power, a sixth lens having a negative refractive power, a seventh lens having a positive refractive power, and an eighth lens having a negative refractive power. The imaging lens system satisfies TTL/IMGHT <1.5, wherein TTL is the distance from the object side surface of the first lens to the imaging surface, and IMGHT is half of the diagonal length of the imaging surface.

The first to seventh lenses may be meniscus lenses, and the eighth lens may be a biconcave lens.

The first lens may be thicker than each of the other lenses along the optical axis.

The second lens may be thinner than each of the other lenses along the optical axis.

Other features and aspects will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

Drawings

Fig. 1 is a diagram showing a first example of an imaging lens system.

Fig. 2 is an aberration curve of the imaging lens system shown in fig. 1.

Fig. 3 is a diagram showing a second example of the imaging lens system.

Fig. 4 is an aberration curve of the imaging lens system shown in fig. 3.

Fig. 5 is a diagram showing a third example of the imaging lens system.

Fig. 6 is an aberration curve of the imaging lens system shown in fig. 5.

Fig. 7 is a diagram showing a fourth example of the imaging lens system.

Fig. 8 is an aberration curve of the imaging lens system shown in fig. 7.

Fig. 9 is a diagram showing a fifth example of the imaging lens system.

Fig. 10 is an aberration curve of the imaging lens system shown in fig. 9.

Like reference numerals refer to like elements throughout the drawings and the detailed description. The figures may not be drawn to scale and the relative sizes, proportions and depictions of the elements in the figures may be exaggerated for clarity, illustration and convenience.

Detailed Description

The following detailed description is provided to assist the reader in obtaining a thorough understanding of the methods, apparatuses, and/or systems described herein. Various changes, modifications, and equivalents of the methods, devices, and/or systems described herein will, however, be apparent to those of ordinary skill in the art. The sequence of operations described in this application is merely an example and is not limited to the order set forth in this application, except for operations that must occur in a particular order, but may be varied as would be apparent to one of ordinary skill in the art. Also, descriptions of functions and configurations that will be well known to those of ordinary skill in the art may be omitted for clarity and conciseness.

The features described in this application may be embodied in different forms and should not be construed as limited to the examples described in this application. Rather, the examples described herein are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It should be noted that in this application, the use of the word "may" with respect to an example or embodiment, such as with respect to what the example or embodiment may comprise or implement, means that there is at least one example or embodiment in which such features are comprised or implemented, and that all examples and embodiments are not limited thereto.

Throughout the specification, when an element such as a layer, region or substrate is described as being "on," "connected to" or "coupled to" another element, it can be directly on, "connected to" or "coupled to" the other element or one or more other elements may be present between the element and the other element. In contrast, when an element is referred to as being "directly on," "directly connected to" or "directly coupled to" another element, there may be no other elements intervening between the element and the other element.

As used in this application, the term "and/or" includes any one of the associated listed items as well as any combination of any two or more items.

Although terms such as "first", "second", and "third" may be used herein to describe various elements, components, regions, layers or sections, these elements, components, regions, layers or sections are not limited by these terms. Rather, these terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first member, first component, first region, first layer, or first portion referred to in these examples may also be referred to as a second member, second component, second region, second layer, or second portion without departing from the teachings of the examples described in this application.

Spatially relative terms such as "above … …", "upper", "below … …" and "lower" may be used herein for descriptive convenience to describe one element's relationship to another element as illustrated in the figures. These spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "upper" relative to other elements would then be oriented "below" or "lower" relative to the other elements. Thus, the term "above … …" encompasses both orientations of "above and" below. The device may also be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used in this application should be interpreted accordingly.

The terminology used in the present application is for the purpose of describing the various examples only and is not intended to be limiting of the disclosure. The articles "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," and "having" specify the presence of stated features, integers, operations, elements, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, operations, elements, components, and/or groups thereof.

Variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, may be expected. Accordingly, examples described in this application are not limited to the specific shapes shown in the drawings, but include shape changes that occur during manufacturing.

The features of the examples described in this application may be combined in various ways that will be apparent after understanding the disclosure of this application. Further, while the examples described in this application have a variety of configurations, other configurations are possible as will be apparent after understanding the disclosure of this application.

The figures may not be drawn to scale and the relative sizes, proportions and depictions of the elements in the figures may be exaggerated for clarity, illustration and convenience.

In an example, the first lens refers to a lens closest to an object (or subject), and the eighth lens refers to a lens closest to an imaging plane (or image sensor). In the example, the unit of the radius of curvature, the unit of the thickness, the unit of TTL (distance from the object side surface of the first lens to the imaging surface), the unit of 2IMGHT (diagonal length of the imaging surface), and the unit of the focal length are expressed in millimeters (mm). Units of the FOV are expressed in degrees (°).

The thickness of the lenses, the interval between the lenses, and TTL mean the distance on the optical axis. In addition, in the description of the shape of the lens, a configuration in which one surface is convex means that the optical axis region of the surface is convex, and a configuration in which one surface is concave means that the optical axis region of the surface is concave. Thus, even when one face of the lens is described as convex, the edge of the lens may be concave. Similarly, even when it is described that one face of the lens is concave, the edge of the lens may be convex.

The imaging lens system may include eight lenses. For example, the imaging lens system may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, which are arranged in this order from the object side. The first to eighth lenses may be disposed with a predetermined interval therebetween. For example, the image side and object side of adjacent lenses do not contact each other in the paraxial region. Therefore, even when the image side surface of one lens in the figure is in contact with the object side surface of the other lens, the image side surface and the object side surface of the two lenses are not actually in contact with each other.

The first lens may have an optical power. One face of the first lens may be convex. For example, the first lens may have a convex object side. The first lens may include an aspheric surface. For example, both faces of the first lens may be aspherical. The first lens may be formed of a material having high light transmittance and excellent workability. For example, the first lens may be manufactured using a plastic material. The first lens may have a predetermined refractive index. For example, the refractive index of the first lens may be less than 1.6. The first lens may have a predetermined abbe number. For example, the abbe number of the first lens may be 50 or more. The first lens may have a predetermined focal length. For example, the focal length of the first lens may be 4.0mm to 6.8 mm.

The second lens may have an optical power. For example, the second lens may have a negative refractive power. One face of the second lens may be concave. For example, the second lens may have a concave image side surface. The second lens may include an aspheric surface. For example, both faces of the second lens may be aspherical. The second lens may be formed of a material having high light transmittance and excellent workability. For example, the second lens may be manufactured using a plastic material. The second lens may have a predetermined refractive index. For example, the refractive index of the second lens may be 1.6 or more. The second lens may have a predetermined abbe number. For example, the abbe number of the second lens may be less than 23. The second lens may have a predetermined focal length. For example, the focal length of the second lens may be-20 mm to-10 mm.

The third lens may have an optical power. One face of the third lens may be convex. For example, the third lens may have a convex object side. The third lens may include an aspheric surface. For example, both faces of the third lens may be aspherical. The third lens may be formed of a material having high light transmittance and excellent workability. For example, the third lens may be manufactured using a plastic material. The third lens may have a refractive index greater than that of the first lens. For example, the refractive index of the third lens may be 1.6 or more. The third lens may have a predetermined abbe number. For example, the third lens may have an abbe number of less than 23. The third lens may have a predetermined focal length. For example, the focal length of the third lens may be-65 mm to-30 mm.

The fourth lens may have an optical power. One face of the fourth lens may be convex. For example, the fourth lens may have a convex object side. The fourth lens may include an aspheric surface. For example, both faces of the fourth lens may be aspherical. The fourth lens may be formed of a material having high light transmittance and excellent workability. For example, the fourth lens may be manufactured using a plastic material. The fourth lens may have a refractive index smaller than that of the third lens. For example, the refractive index of the fourth lens may be less than 1.6. The fourth lens may have a predetermined abbe number. For example, the abbe number of the fourth lens may be larger than that of the third lens. The fourth lens may have a predetermined focal length. For example, the focal length of the fourth lens may be less than-100 mm or 30mm or more.

The fifth lens may have an optical power. One face of the fifth lens may be concave. For example, the fifth lens may have a concave image side surface. The fifth lens may have a shape with an inflection point. For example, at least one of the object-side surface and the image-side surface of the fifth lens may have an inflection point. The fifth lens may include an aspheric surface. For example, both faces of the fifth lens may be aspherical. The fifth lens may be formed of a material having high light transmittance and excellent workability. For example, the fifth lens may be manufactured using a plastic material. The fifth lens may have a predetermined refractive index. For example, the fifth lens may have a refractive index smaller than that of the third lens. The fifth lens may have a predetermined abbe number. For example, the abbe number of the fifth lens may be larger than that of the third lens. The fifth lens may have a predetermined focal length. For example, the focal length of the fifth lens may be-50 mm or less or 30mm or more.

The sixth lens may have an optical power. One face of the sixth lens may be convex. For example, the sixth lens may have a convex object side. The sixth lens may have a shape with an inflection point. For example, at least one of the object-side surface and the image-side surface of the sixth lens may have an inflection point. The sixth lens may include an aspheric surface. For example, both faces of the sixth lens may be aspherical. The sixth lens may be formed of a material having high light transmittance and excellent workability. For example, the sixth lens may be manufactured using a plastic material. The sixth lens may have a predetermined refractive index. For example, the refractive index of the sixth lens may be greater than or equal to the refractive index of the fifth lens. The sixth lens may have a predetermined abbe number. For example, the abbe number of the sixth lens may be 25 or more and less than 40. The sixth lens may have a predetermined focal length. For example, the focal length of the sixth lens may be-38 mm to-10 mm.

The seventh lens may have an optical power. One face of the seventh lens may be convex. For example, the seventh lens may have a convex object side. The seventh lens may have a shape with an inflection point. For example, at least one of the object-side surface and the image-side surface of the seventh lens may have an inflection point. The seventh lens may include an aspherical surface. For example, both faces of the seventh lens may be aspherical. The seventh lens may be formed of a material having high light transmittance and excellent workability. For example, the seventh lens may be manufactured using a plastic material. The seventh lens may have a predetermined refractive index. For example, the refractive index of the seventh lens may be smaller than that of the sixth lens. The seventh lens may have an abbe number larger than that of the sixth lens. For example, the abbe number of the seventh lens may be 50 or more. The seventh lens may have a predetermined focal length. For example, the focal length of the seventh lens may be 3.6mm to 7.4 mm.

The eighth lens may have an optical power. At least one surface of the eighth lens may be concave. For example, the eighth lens may have a concave image side surface in the paraxial region. The eighth lens may have a shape with an inflection point. For example, at least one of the object side surface and the image side surface of the eighth lens may have an inflection point. The eighth lens may include an aspherical surface. For example, both faces of the eighth lens may be aspherical. The eighth lens may be formed of a material having high light transmittance and excellent workability. For example, the eighth lens may be manufactured using a plastic material. The eighth lens may have a predetermined refractive index. For example, the refractive index of the eighth lens may be smaller than that of the sixth lens. The eighth lens may have an abbe number larger than that of the sixth lens. For example, the abbe number of the eighth lens may be 50 or more. The eighth lens may have a predetermined focal length. For example, the focal length of the eighth lens may be-6.2 mm to-3.1 mm.

In the imaging lens system, the first lens may be the thickest lens. For example, the thickness of the first lens along the optical axis at the center thereof may be larger than the thicknesses of the other lenses (second lens to eighth lens) along the optical axis at the respective centers thereof.

In the imaging lens system, the second lens may be the thinnest lens. For example, the thickness of the second lens along the optical axis at the center thereof may be smaller than the thicknesses of the other lenses (the first lens and the third to eighth lenses) along the optical axis at the respective centers thereof.

Each of the first to eighth lenses may include an aspherical surface. The aspherical surface of each of the first to eighth lenses may be represented by equation 1 below:

[ equation 1]

In equation 1, "c" is the reciprocal of the radius of curvature of each lens, "k" is a conic constant, "r" is the distance from a certain point on the aspherical surface of the lens to the optical axis, "a to J" are aspherical constants, and "Z" (or SAG) is the distance from a certain point on the aspherical surface to the vertex of the aspherical surface in the optical axis direction.

The imaging lens system may further include a filter, an image sensor, and a diaphragm. The filter may be disposed between the eighth lens and the image sensor. The filter may be configured to block light of a particular wavelength. For example, the optical filter may block infrared wavelengths of light. The image sensor may form an imaging plane. For example, the surface of the image sensor may form an imaging plane. The diaphragm may be arranged to adjust the amount of light incident on the lens. For example, a diaphragm may be disposed between the second lens and the third lens.

The imaging lens system may have a predetermined focal length. For example, the focal length f of the imaging lens system may be 5.6mm to 7.0 mm. The imaging lens system may have a comparatively large-sized imaging surface to achieve high resolution. For example, the diagonal length (2IMGHT) of the imaging plane of the imaging lens system may be 10mm to 14 mm.

The imaging lens system may satisfy one or more of the following conditional expressions:

TTL/IMGHT<1.5

0.05<TTL/FOV<0.2

0.2<T8/T7<0.9

f number is less than or equal to 1.7

78°≤FOV≤85°

0.5<f1/f<1.0

-4.0<f2/f1<-2.0

0.2<f2/f3<0.5

-5.0<f6/f7<-2.0

-3.0<f7/f8<-1.0

In the conditional expressions, TTL is a distance from the object side surface of the first lens to the imaging plane, IMGHT is 1/2 of a diagonal length of the imaging plane, T7 is a thickness of the seventh lens at its center along the optical axis, T8 is a thickness of the eighth lens at its center along the optical axis, FOV is a field angle of the imaging lens system, f is a focal length of the imaging lens system, f1 is a focal length of the first lens, f2 is a focal length of the second lens, f3 is a focal length of the third lens, f6 is a focal length of the sixth lens, f7 is a focal length of the seventh lens, and f8 is a focal length of the eighth lens.

The imaging lens system may further satisfy one or more of the following conditional expressions:

0.4<f1/f7<1.2

-1.4<f1/f8<-0.4

18<(V2+V3)/2<22

V2<40

V3<V6<V7

T5<T4

2.0<(R11+R12)/(R11-R12)<5.0

0.72<DL1L4/DL5L8<0.82

1.06<f/IMGHT<1.12

in the above conditional expressions, V2 is an abbe number of the second lens, V3 is an abbe number of the third lens, V6 is an abbe number of the sixth lens, V7 is an abbe number of the seventh lens, T4 is a thickness of the fourth lens at its center along the optical axis, T5 is a thickness of the fifth lens at its center along the optical axis, R11 is a radius of curvature of an object-side surface of the sixth lens, R12 is a radius of curvature of an image-side surface of the sixth lens, DL1L4 is a distance from the object-side surface of the first lens to the image-side surface of the fourth lens, and DL5L8 is a distance from the object-side surface of the fifth lens to the image-side surface of the eighth lens.

f number is less than or equal to 1.64

0.4<|f3/f5|<1.6

2.0<(R5+R6)/(R5-R6)<4.0

-2.0<(R13+R14)/(R13-R14)<-0.8

1.0<f/f7<1.3

In the above conditional expressions, R5 is a radius of curvature of an object-side surface of the third lens, R6 is a radius of curvature of an image-side surface of the third lens, R13 is a radius of curvature of an object-side surface of the seventh lens, and R14 is a radius of curvature of an image-side surface of the seventh lens.

In the following description, various examples of the imaging lens system will be described.

A first example of the imaging lens system will be described with reference to fig. 1.

The imaging lens system 100 may include a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, and an eighth lens 180.

The first lens 110 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. The second lens 120 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. The third lens 130 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. The fourth lens 140 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. The fifth lens 150 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of the object-side surface and the image-side surface of the fifth lens 150. The sixth lens 160 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the sixth lens 160. The seventh lens 170 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of the object-side surface and the image-side surface of the seventh lens 170. The eighth lens 180 may have a negative refractive power, and a concave object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object side surface and an image side surface of the eighth lens 180.

The imaging lens system 100 may further include a filter IF, an image sensor IMG, and a diaphragm ST. The filter IF may be disposed between the eighth lens 180 and the image sensor IMG. The image sensor IMG may provide a surface on which light refracted by the first through eighth lenses 110 through 180 is formed. One surface of the image sensor IMG may be approximately the same size as the imaging plane. For example, the diagonal length of the imaging plane (2IMGHT) refers to the diagonal length of the image sensor IMG, and the height of the imaging plane may refer to the distance from the center to the edge of the optical axis of the image sensor IMG. The stop ST may be disposed between the second lens 120 and the third lens 130.

Table 1 and table 2 list lens characteristics and aspheric values of the imaging lens system 100. Fig. 2 is an aberration curve of the imaging lens system 100 of the above configuration.

TABLE 1

TABLE 2

A second example of the imaging lens system will be described with reference to fig. 3.

The imaging lens system 200 may include a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, a seventh lens 270, and an eighth lens 280.

The first lens 210 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. The second lens 220 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. The third lens 230 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. Fourth lens 240 may have a positive refractive power and may have a convex object-side surface and a concave image-side surface. The fifth lens 250 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the fifth lens 250. The sixth lens 260 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the sixth lens 260. The seventh lens 270 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of the object-side surface and the image-side surface of the seventh lens 270. The eighth lens 280 may have a negative refractive power and may have a concave object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the eighth lens 280.

The imaging lens system 200 may further include a filter IF, an image sensor IMG, and a diaphragm ST. The filter IF may be disposed between the eighth lens 280 and the image sensor IMG. The image sensor IMG may provide a surface on which light refracted by the first to eighth lenses 210 to 280 is formed. One surface of the image sensor IMG may be approximately the same size as the imaging plane. For example, the diagonal length of the imaging plane (2IMGHT) refers to the diagonal length of the image sensor IMG, and the height of the imaging plane may refer to the distance from the center to the edge of the optical axis of the image sensor IMG. The stop ST may be disposed between the second lens 220 and the third lens 230.

Table 3 and table 4 list lens characteristics and aspheric values of the imaging lens system 200. Fig. 4 is an aberration curve of the imaging lens system 200 of the above configuration.

TABLE 3

TABLE 4

Flour mark	K	A	B	C	D	E	F	G	H	J
											S1	-0.977501	-0.003935	0.03566	-0.06648	0.07812	-0.05719	0.02357	-0.001832	-0.003927	0.002605
S2	24.256772	-0.01734	0.02382	-0.04735	0.09105	-0.1273	0.1247	-0.08725	0.04424	-0.01632
											S3	16.447043	-0.04114	0.1252	-0.3314	0.5847	-0.6813	0.5346	-0.2841	0.09972	-0.02093
S4	2.4777825	-0.02548	0.1177	-0.3338	0.515	-0.3284	-0.2047	0.6032	-0.5729	0.3107
											S5	0	0.0001756	-0.08569	0.3416	-0.9226	1.758	-2.428	2.459	-1.829	0.9952
S6	56.350823	-0.01711	0.02414	-0.09787	0.228	-0.3404	0.3182	-0.173	0.03554	0.01898
											S7	98.884228	-0.03447	0.2124	-1.059	3.234	-6.491	8.929	-8.669	6.038	-3.03
S8	-99.00005	-0.03892	0.08133	-0.01505	-0.6266	2.045	-3.46	3.728	-2.737	1.404
											S9	0	-0.03305	0.006005	-0.09955	0.3424	-0.6687	0.8536	-0.7539	0.4727	-0.2123
S10	0	-0.04115	0.02906	-0.06185	0.089	-0.09332	0.07136	-0.03976	0.01616	-0.004776
											S11	0	-0.08603	0.09214	-0.08082	0.05511	-0.03092	0.01465	-0.005795	0.001809	-0.00042
S12	-39.38114	-0.1047	0.1	-0.07676	0.0443	-0.01861	0.005745	-0.001373	0.0002715	-4.57E-05
											S13	-7.365153	-0.02249	0.01129	-0.00247	-0.002451	0.00202	-0.000725	0.0001571	-2.25E-05	2.215E-06
S14	23.383791	0.01202	-0.007542	0.007938	-0.006811	0.003202	-0.000929	0.0001797	-2.41E-05	2.286E-06
											S15	-1.492134	-0.07336	0.04525	-0.0173	0.003788	-0.000412	2.16E-06	5.752E-06	-8.72E-07	7.101E-08
S16	-19.10332	-0.06043	0.03583	-0.01475	0.004065	-0.000781	0.0001088	-1.12E-05	8.63E-07	-4.94E-08

A third example of the imaging lens system will be described with reference to fig. 5.

The imaging lens system 300 may include a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, a seventh lens 370, and an eighth lens 380.

The first lens 310 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. The second lens 320 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. The third lens 330 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. The fourth lens 340 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. Fifth lens 350 may have a positive refractive power and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the fifth lens 350. The sixth lens 360 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the sixth lens 360. The seventh lens 370 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the seventh lens 370. The eighth lens 380 may have a negative refractive power and may have a concave object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the eighth lens 380.

The imaging lens system 300 may further include a filter IF, an image sensor IMG, and a diaphragm ST. The filter IF may be disposed between the eighth lens 380 and the image sensor IMG. The image sensor IMG may provide a surface on which light refracted by the first through eighth lenses 310 through 380 is formed. One surface of the image sensor IMG may be approximately the same size as the imaging plane. For example, the diagonal length of the imaging plane (2IMGHT) refers to the diagonal length of the image sensor IMG, and the height of the imaging plane may refer to the distance from the center to the edge of the optical axis of the image sensor IMG. The stop ST may be disposed between the second lens 320 and the third lens 330.

Table 5 and table 6 list lens characteristics and aspheric values of the imaging lens system 300. Fig. 6 is an aberration curve of the imaging lens system 300 configured as described above.

TABLE 5

TABLE 6

Flour mark	K	A	B	C	D	E	F	G	H	J
											S1	-1.021828	-0.01896	0.1021	-0.2305	0.3375	-0.3375	0.239	-0.1221	0.04541	-0.01224
S2	27.483091	-0.02125	0.02647	-0.04209	0.08433	-0.1286	0.1344	-0.09851	0.05187	-0.01979
											S3	16.571645	-0.0269	0.02934	-0.02785	0.005501	0.06759	-0.1621	0.1991	-0.1548	0.08107
S4	2.329664	-0.008104	0.01857	-0.07846	0.2349	-0.4188	0.4574	-0.2903	0.0682	0.04808
											S5	0	0.03542	-0.3975	1.734	-4.822	9.088	-12.06	11.52	-8.02	4.072
S6	95.620843	-0.04713	0.2007	-0.809	2.045	-3.463	4.085	-3.434	2.081	-0.9096
											S7	92.803604	-0.04517	0.2372	-1.015	2.742	-4.991	6.357	-5.802	3.841	-1.847
S8	19.623148	-0.0422	0.1464	-0.5006	1.076	-1.54	1.523	-1.066	0.5322	-0.1886
											S9	0	-0.03346	0.01336	-0.1054	0.32	-0.589	0.7273	-0.6276	0.385	-0.1686
S10	0	-0.03637	0.04988	-0.1559	0.2794	-0.3299	0.2711	-0.1595	0.06818	-0.02119
											S11	0	-0.05656	0.03784	-0.02001	0.003531	0.003559	-0.003956	0.00219	-0.000802	0.000204
S12	-37.93685	-0.06085	0.01424	0.01542	-0.02468	0.01805	-0.00854	0.002828	-0.000672	0.0001149
											S13	-9.92841	-0.006148	-0.01069	0.01178	-0.008163	0.003492	-0.000994	0.000197	-2.78E-05	2.817E-06
S14	46.8868	0.02276	-0.0168	0.01054	-0.005761	0.002195	-0.000576	0.0001064	-1.41E-05	1.345E-06
											S15	-1.893815	-0.07156	0.03583	-0.01332	0.003704	-0.000717	9.637E-05	-9.14E-06	6.184E-07	-2.98E-08
S16	-25.29874	-0.04909	0.02346	-0.008608	0.002275	-0.000431	5.922E-05	-5.95E-06	4.389E-07	-2.37E-08

A fourth example of the imaging lens system will be described with reference to fig. 7.

The imaging lens system 400 may include a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, a seventh lens 470, and an eighth lens 480.

The first lens 410 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. The second lens 420 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. The third lens 430 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. Fourth lens 440 may have positive optical power and may have a convex object-side surface and a concave image-side surface. The fifth lens 450 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the fifth lens 450. The sixth lens 460 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of the object-side surface and the image-side surface of the sixth lens 460. The seventh lens 470 may have a positive refractive power and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of the object-side surface and the image-side surface of the seventh lens 470. The eighth lens 480 may have a negative refractive power and may have a concave object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the eighth lens 480.

The imaging lens system 400 may further include a filter IF, an image sensor IMG, and a diaphragm ST. The filter IF may be disposed between the eighth lens 480 and the image sensor IMG. The image sensor IMG may provide a surface on which light refracted by the first through eighth lenses 410 through 480 is formed. One surface of the image sensor IMG may be approximately the same size as the imaging plane. For example, the diagonal length of the imaging plane (2IMGHT) refers to the diagonal length of the image sensor IMG, and the height of the imaging plane may refer to the distance from the center to the edge of the optical axis of the image sensor IMG. The stop ST may be disposed between the second lens 420 and the third lens 430.

Table 7 and table 8 list lens characteristics and aspheric values of the imaging lens system 400. Fig. 8 is an aberration curve of the imaging lens system 400 configured as described above.

TABLE 7

TABLE 8

A fifth example of the imaging lens system will be described with reference to fig. 9.

Imaging lens system 500 may include a first lens 510, a second lens 520, a third lens 530, a fourth lens 540, a fifth lens 550, a sixth lens 560, a seventh lens 570, and an eighth lens 580.

The first lens 510 may have positive refractive power, and may have a convex object-side surface and a concave image-side surface. The second lens 520 may have a negative refractive power and may have a convex object-side surface and a concave image-side surface. The third lens 530 may have a negative refractive power, and may have a convex object-side surface and a concave image-side surface. The fourth lens 540 may have a negative refractive power and may have a convex object-side surface and a concave image-side surface. The fifth lens 550 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the fifth lens 550. Sixth lens 560 may have a negative refractive power and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the sixth lens 560. The seventh lens 570 may have a positive refractive power, and may have a convex object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object side surface and an image side surface of the seventh lens 570. The eighth lens 580 may have a negative refractive power, and may have a concave object-side surface and a concave image-side surface. An inflection point may be formed on at least one of an object-side surface and an image-side surface of the eighth lens 580.

The imaging lens system 500 may further include a filter IF, an image sensor IMG, and a diaphragm ST. The filter IF may be disposed between the eighth lens 580 and the image sensor IMG. The image sensor IMG may provide a surface on which light refracted by the first to eighth lenses 510 to 580 is formed. One surface of the image sensor IMG may be approximately the same size as the imaging plane. For example, the diagonal length of the imaging plane (2IMGHT) refers to the diagonal length of the image sensor IMG, and the height of the imaging plane may refer to the distance from the center to the edge of the optical axis of the image sensor IMG. The stop ST may be disposed between the second lens 520 and the third lens 530.

Table 9 and table 10 list lens characteristics and aspheric values of the imaging lens system 500. Fig. 10 is an aberration curve of the imaging lens system 500 configured as described above.

TABLE 9

Watch 10

Flour mark	K	A	B	C	D	E	F	G	H	J
											S1	-1.028837	-0.02409	0.1446	-0.3787	0.6314	-0.7099	0.5594	-0.3161	0.1294	-0.03841
S2	27.139418	-0.01912	0.01984	-0.01858	0.03317	-0.06354	0.0825	-0.07178	0.04322	-0.01831
											S3	16.56626	-0.03611	0.08325	-0.1934	0.3467	-0.4275	0.3499	-0.18	0.04606	0.005663
S4	2.3619195	-0.006635	-0.02015	0.1695	-0.6002	1.364	-2.14	2.391	-1.928	1.124
											S5	0	0.03964	-0.4617	2.104	-6.062	11.76	-16	15.64	-11.12	5.753
S6	98.932938	-0.05194	0.2269	-0.8855	2.193	-3.673	4.319	-3.642	2.225	-0.9845
											S7	92.330151	-0.03483	0.1489	-0.6154	1.616	-2.873	3.577	-3.193	2.069	-0.9745
S8	-98.98639	-0.0416	0.134	-0.4795	1.094	-1.666	1.759	-1.327	0.7252	-0.2882
											S9	0	-0.03919	0.02504	-0.1109	0.3044	-0.5401	0.652	-0.5516	0.3318	-0.1424
S10	0	-0.03933	0.05215	-0.1519	0.2678	-0.3165	0.2629	-0.1574	0.06872	-0.0219
											S11	0	-0.06085	0.0609	-0.05644	0.0367	-0.01688	0.005064	-0.000733	-0.0001	8.014E-05
S12	-36.84334	-0.08749	0.07584	-0.05801	0.03358	-0.01451	0.004584	-0.001033	0.0001598	-1.57E-05
											S13	-9.956325	-0.01164	6.404E-05	0.000979	-0.002315	0.001509	-0.000532	0.0001191	-1.81E-05	1.903E-06
S14	-84.33771	0.02575	-0.01685	0.007841	-0.00402	0.001651	-0.000474	9.442E-05	-1.33E-05	1.33E-06
											S15	-1.549727	-0.06796	0.03522	-0.01412	0.004139	-0.000819	0.0001098	-1.01E-05	6.502E-07	-2.85E-08
S16	-23.9777	-0.04939	0.02417	-0.009403	0.002602	-0.000508	0.0000709	-7.18E-06	5.316E-07	-2.87E-08

Tables 11 and 12 list optical characteristic values and values of conditional expressions of the imaging lens systems of the first to fifth examples. In table 11, BFL refers to the distance from the image-side surface of the eighth lens to the imaging surface.

TABLE 11

TABLE 12

According to the above example, the performance of the compact camera can be improved.

While the present disclosure includes specific examples, it will be apparent upon an understanding of the present disclosure that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described in this application are to be considered in a descriptive sense only and not for purposes of limitation. The description of features or aspects in each example should be understood to be applicable to similar features or aspects in other examples. Suitable results may still be achieved if the described techniques are performed in a different order and/or if components in the described systems, architectures, devices, or circuits are combined in a different manner and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the present disclosure is defined not by the specific embodiments but by the claims and their equivalents, and all modifications within the scope of the claims and their equivalents should be understood as being included in the present disclosure.

Claims

1. An imaging lens system comprising:

a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in this order in a direction from an object side to an image forming surface, wherein the first lens has a positive refractive power, the second lens has a negative refractive power, the third lens has a negative refractive power, the fourth lens has a positive refractive power, the fifth lens has a positive refractive power, the sixth lens has a negative refractive power, the seventh lens has a positive refractive power, and the eighth lens has a negative refractive power, the eighth lens has a concave object-side surface in a paraxial region, and at least one of the first lens to the eighth lens has an aspherical surface,

wherein the imaging lens system has a total of eight lenses, an

Wherein TTL/IMGHT <1.5, where TTL is a distance from an object-side surface of the first lens element to the imaging plane, and IMGHT is half a diagonal length of the imaging plane.

2. The imaging lens system of claim 1, wherein the second lens has a concave image side surface.

3. The imaging lens system of claim 1, wherein the fifth lens has a concave image side surface.

4. The imaging lens system according to claim 1,

0.5<f1/f<1.0，

where f is a focal length of the imaging lens system, and f1 is a focal length of the first lens.

5. The imaging lens system of claim 1, wherein the second lens has an abbe number less than 40.

6. The imaging lens system of claim 1,

0.05mm/° < TTL/FOV <0.2 mm/°，

wherein the FOV is a field angle of the imaging lens system.

7. The imaging lens system of claim 1,

0.2<T8/T7<0.9，

wherein T7 is a thickness of the seventh lens at a center thereof along an optical axis, and T8 is a thickness of the eighth lens at a center thereof along the optical axis.

8. An imaging lens system comprising:

a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in this order in a direction from an object side to an image forming surface, wherein the first lens has a positive refractive power, the second lens has a negative refractive power, the third lens has a negative refractive power, the fourth lens has a positive refractive power, the fifth lens has a positive refractive power, the sixth lens has a negative refractive power, the seventh lens has a positive refractive power, and the eighth lens has a negative refractive power, the sixth lens has a concave image side surface, the eighth lens has a concave object side surface, and at least one of the first lens to the eighth lens has an aspherical surface,

wherein the imaging lens system has a total of eight lenses, an

9. The imaging lens system according to claim 8, wherein an F-number of the imaging lens system is 1.7 or less.

10. The imaging lens system of claim 8,

-4.0<f2/f1<-2.0，

wherein f1 is the focal length of the first lens, and f2 is the focal length of the second lens.

11. The imaging lens system of claim 8,

0.2<f2/f3<0.5，

wherein f2 is a focal length of the second lens, and f3 is a focal length of the third lens.

12. The imaging lens system of claim 8,

-5.0<f6/f7<-2.0，

wherein f6 is a focal length of the sixth lens, and f7 is a focal length of the seventh lens.

13. The imaging lens system of claim 8,

-3.0<f7/f8<-1.0，

wherein f7 is a focal length of the seventh lens, and f8 is a focal length of the eighth lens.

14. An imaging lens system comprising:

a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in order in a direction from an object side to an image forming surface, wherein the first lens has a positive refractive power, the second lens has a negative refractive power, the third lens has a negative refractive power, the fourth lens has a positive refractive power, the fifth lens has a positive refractive power, the sixth lens has a negative refractive power, the seventh lens has a positive refractive power, and the eighth lens has a negative refractive power, at least one of the first lens to the eighth lens having an aspherical surface,

wherein the imaging lens system has a total of eight lenses, an

Wherein TTL/IMGHT is less than 1.5, wherein TTL is a distance from an object side surface of the first lens to the imaging plane, and IMGHT is half of a diagonal length of the imaging plane.

15. The imaging lens system according to claim 14, wherein the first to seventh lenses are meniscus lenses, and the eighth lens is a biconcave lens.

16. The imaging lens system of claim 14, wherein the first lens is thicker than each of the other lenses along an optical axis.

17. The imaging lens system of claim 14, wherein the second lens is thinner than each of the other lenses along an optical axis.